Is there a way to equalize the thickness of my grease pencil drawing over an entire scene? or per entire frame?
Solution: Thickness Modifier

Check my fast scribbled helper showing the might of the modifier.


Don't laugh, well you can, but only if this helped you, then i can laugh with you.
Joke aside, the modifier affects all layers under the same Stroke Object. It's slightly more work if you have multiple Stroke Objects. Then all need a modifier, but you can select all Stroke Objects and once you have "Normalize" active and the Thickness Factor set, just right click on each and use "Copy to selected" for each, that way all Stroke Objects or rather their Layers will be normalized and the same thickness.